COMMENT
  Variables are of six types, with arrays of each type being supported:

    CHAR (or BYTE)              FIXED
    STRING                      REAL
    INTEGER                     REAL.DOUBLE

  Simple variables may be declared using the VAR, COMMON, and BASED keywords.

  Arrays are declared using the DIM keyword and, if applicable, the COMMON or
  BASE keyword. The maximum length of a string variable may be specified as
  part of the declaration; if omitted, the default length is 80. Examples follow:

    VAR FN = STRING:15
    VAR X, Y, Z = INTEGER
    VAR RATE = REAL

    BASED IOBYTE = BYTE
    COMMON ERROR_NUMBER = INTEGER

    DIM REAL TEMPERATURES(20)
    DIM INTEGER MATRIX(4,4)
    DIM STRING:20 LASTNAMES(100)
    DIM BASE BYTE FCB(16)
    DIM COMMON INTEGER HISCORES(10)

  Simple variables declared with VAR are placed in the data segment of the
  compiled code.  Variables declared COMMON are placed in a special data
  segment that will be preserved during program chaining. Variables
  declared using the BASED statement are positioned at run-time
  using the BASE statement to specify the address, e.g.,

     BASE IOBYTE AT 0003H

  Arrays are dynamically created at run-time and do not occupy space in the
  compiled code unless they are declared as COMMON.  Arrays declared as BASE
  are positioned at run-time using the LOCATE statement, e.g.,

     LOCATE FCB AT 5CH

  CHAR or BYTE variables occupy 1 byte.  Character constants may be specified
  using single quotes, e.g., 'A', or in decimal or hexadecimal form, e.g., 64
  or 40H.

  INTEGER variables occupy 2 bytes and may take signed decimal values from
  -32768 to +32767 or unsigned hexadecimal values from 0000H to FFFFH.

  FIXED variables occupy 6 bytes and can represent a sign and 11 digits in
  packed BCD form, with 3 digits to the right of the decimal point. The
  maximum value that can be represented is 99,999,999.995.

  REAL variables occupy 4 bytes and can represent floating point values up
  to 6 digits. Constants may be expressed as, e.g., 3.14159 or 3.14159E+1.

  REAL.DOUBLE variables occupy 7 bytes and can represent floating point values
  up to 12 digits.
END